1. Field of the Invention
This invention generally relates to the field of wireless communications. More particularly, the present invention relates to a novel and improved method and system for determining the selection of a mobile service data option in a wireless communications network having data service support.
2. Description of Related Art
Recent innovations in wireless communication and computer-related technologies, as well as the unprecedented growth of Internet subscribers, have paved the way for mobile computing. In fact the popularity of mobile computing has placed greater demands on the current Internet infrastructure to provide mobile users with more support. One crucial part of meeting these demands and providing users with such support is the use of Code Division Multiple Access (CDMA) technology in wireless communication systems.
CDMA technology has been used in military and intelligence-gathering satellite communication systems for decades. However, only recently has CDMA""s potential for wireless commercial communication applications been exploited. Unlike conventional analog and digital communication systems, which divide the available frequency spectrum into narrow channels and assign conversations to each channel, CDMA systems assign a unique code to each conversation and spread the plurality of simultaneous conversations across a wideband spread spectrum bandwidth. As long as the receiving apparatus has the correct code, it can successfully detect and select its conversation from the other conversations concurrently transmitted over the same bandwidth in the CDMA system. The standard for CDMA (i.e., spread spectrum) wideband wireless communication systems is generally provided by the Telecommunications Industry Association/Electronics Industries Association Interim Standard 95 (TIA/EIA IS-95), entitled xe2x80x9cMOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL-MODE WIDEBAND SPREAD SPECTRUM CELLULAR SYSTEMxe2x80x9d, published in July 1993 and herein incorporated by reference.
Even more recently, CDMA technology has been recognized as ideal for accommodating data service traffic as well. In fact, TIA/EIA IS-707, as defined in xe2x80x9cDATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMSxe2x80x9d, published in February 1998 and herein incorporated by reference, provides a suite of data service options within a wireless CDMA communication network. This standard includes circuit-switched data/modem emulation services, such as asynchronous data, Group m facsimile, and secure telephone units (STU-III) applications. In addition, it includes packet-switched services, such as Internet-related e-mail and web-browsing capabilities.
These services enable mobile users to use their laptop or palmtop computers to access the Internet. To wit, just as stationary users conventionally employ xe2x80x9cwiredxe2x80x9d communication devices to connect their desktop computers to land-based networks, mobile users can use wireless communication devices (MT2 devices) to connect their mobile laptops to such networks. As used herein, an MT2 device refers to any subscriber station in the wireless communication network that is can be used while in transit or during halts at unspecified points. MT2 devices include portable units (e.g., hand-held personal phones) and units permanently installed in vehicles (e.g., installed mobile phone units), as well as wireless local loop (WLL) telephones.
FIG. 1 illustrates a high-level block diagram of a wireless data communication system in which mobile terminal equipment TE2 device 102 (e.g., laptop or palmtop computer), communicates with an Interworking Function (IWF) 108 via a wireless communication system. The wireless communication system includes a wireless communication device MT2 device 104 and a Base Station/Mobile Switching Center (BS/MSC) 106. The IWF 108 serves as the access point or gateway to the Internet. An L interface couples IWF 108 to BS/MSC 106. Often the IWF 108 will be co-located with the BS/MSC.
The TE2 device 102 is electronically coupled to the MT2 device 104 via the Rm interface. The MT2 device 104 communicates with the BS/MSC 106 via the wireless interface Um. The TE2 device 102 and the MT2 device 104 may be integrated into a single unit or maybe separated out, as in the case of an installed mobile phone unit in which a laptop operates as the TE2 device 102 and the transceiver operates as the MT2 device 104. The combination of the TE2 device 102 and the MT2 device 104, whether integrated or separate, is also referred to as a mobile station (MS)103.
As stated above, CDMA Data Service Options offers direct Internet access via its packet-switch functionality. Specifically, TIA/EIA IS-707.5, entitled xe2x80x9cDATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: PACKET DATA SERVICES,xe2x80x9d published in February 1998 and herein incorporated by reference, defines requirements for support of packet data transmission capability on TIA/EIA IS-95 wideband spread spectrum systems. IS-707.5 specifies a packet data bearer service that may be used for communication between TE2 device 102 and IWF 108 via BS/MSC 106 and provides procedures that can apply to multiple packet data services.
In particular, the IS-707.5 standard specifies the Packet Data Service options that may be used to communicate between the TE2 device 102 and IWF 108 via BS/MSC 106. In doing so, IS-707.5 introduces two protocol option models, which specify the packet data protocol requirements for the Rm interface, Um interface, and the L interface. FIG. 2 depicts one of the protocol option models, the Relay Layer Interface Protocol Option model 200, in which the application running on the TE2 device 102 manages the packet data as well as the network addressing.
At the far left of FIG. 2 is a protocol stack, shown in conventional vertical format that depicts the protocol layers running on the TE2 device 102. At the top of the TE2 protocol stack lies the application layer 202. For mobile users accessing the Internet through Packet Data Service options, the communications applications software such as web browser programs (e.g., Netscape Navigator(trademark), Microsoft Internet Explorer(trademark) etc.) and e-mail/messaging programs (e.g., Eudora(copyright)) comprise the application layer 202 of the TE2 device 102.
As depicted in FIG. 2, the transport layer protocol 204 of the TE2 device 102 maybe the Transmission Control Protocol (TCP). TCP is defined in Request for Comment 793 (RFC 793) entitled, xe2x80x9cTRANSMISSION CONTROL PROTOCOL: DARPA INTERNET PROGRAM PROTOCOL SPECIFICATIONxe2x80x9d, published in September 1981 and herein incorporated by reference. Essentially, TCP provides a reliable transport service to all applications. TCP manages the assembly of messages coming from the TE2 device 102 into packets or datagrams that are transmitted over the Internet.
Alternatively, the transport layer protocol 204 of the TE2 device 102 may implement the User Datagram Protocol (UDP). UDP is defined in Request for Comment 768 (RFC 768) entitled, xe2x80x9cUSER DATAGRAM PROTOCOLxe2x80x9d, published in August 1980 and incorporated by reference. Like TCP, UDP provides a transport service to all applications. However, instead of assembling the messages coming from the TE2 device 102 into packets or datagrams, UDP relies on the application itself to ensure that the messages arrive and that they do so in sequence.
The network layer protocol 206 of the TE2 device 102 is the Internet Protocol (IP), is defined in Request for Comment 791 (RFC 791) entitled, xe2x80x9cINTERNET PROTOCOL: DARPA INTERNET PROGRAM PROTOCOL SPECIFICATIONxe2x80x9d, published in September 1981 and herein incorporated by reference. The IP protocol is the life-blood of the Internet as it handles the addressing and routing functionality for all Internet communications. It achieves this by affixing a 32-bit address to the header of packets, so as to ensure that the packets get to the right destination. Each computer on the network checks the IP address to see where to forward the IP packets.
The link layer protocol 208 of the TE2 device 102 is the Point-to-Point Protocol (PPP) which is described in detail in Request for Comments 1661 (RFC 1661), entitled xe2x80x9cTHE POINT-TO-POINT PROTOCOL (PPP)xe2x80x9d, dated May 1992, and herein incorporated by reference. The PPP protocol is a link layer protocol used to configure, test, and establish the data link connection. The PPP protocol encodes packets coming from upper protocol layers of the TE2 102 device. In order to transmit these IP packets over a serial line link (i.e., TIA/EIA 232-F interface between the TE2 device 102 and the MT2 device 104), and presumably gain a dial-up connection, the PPP protocol encodes the IP packets and xe2x80x9cserializesxe2x80x9d them to facilitate transmission.
Finally, FIG. 2 illustrates that the TE2 protocol stack is logically connected to the protocol stack of the MT2 device 104 over the Rm interface through the relay layer protocol 210. The Rm interface complies with the TIA/EIA-232-F standard, entitled xe2x80x9cINTERFACE BETWEEN DATA TERMINAL EQUIPMENT AND DATA CIRCUIT-TERMINATING EQUIPMENT EMPLOYING SERIAL BINARY DATA INTERCHANGExe2x80x9d, published in October 1997 and herein incorporated by reference.
Central to the Relay Layer Interface Protocol Option model is the notion that the principal link layer connection is established between the TE2 device 102 and the IWF 108. The TE2 device 102 is responsible for all aspects of packet data and network address management. As such, the MT2 device 104 simply behaves as a pipe transmitting the TE2 device 102 frames over the Um interface and the IWF 108 frames over the Rm interface. Therefore, Internet access is achieved without dialing telephone numbers, waiting for modem training/handshaking, or incurring overhead data costs to ensure reliability.
Alternatively, CDMA Data Service Options offer circuit-switched data/modem emulation services, such as Asynchronous Data Services and Fax Services. These service options essentially follow the protocol flow of conventional modem/facsimile dial-up communications. For example, to gain Internet access, mobile users,much like their desktop computer counterparts, use their TE2 devices 102 with application software, having dial-up communication capabilities, to establish a serial communications link to an Internet Service Provider""s (ISP) modem. Specifically, TIA/EIA IS-707.4, entitled xe2x80x9cDATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: ASYNC DATA AND FAX SERVICES,xe2x80x9d published in February 1998 and herein incorporated by reference, defines requirements for support of async and fax services on TIA/EIA IS-95 wideband spread spectrum systems.
An exemplary embodiment of the IS-707.4 Async Data and Fax Services is illustrated in FIG. 3, which depicts the protocol stacks in each of the wireless communication entities. Under the IS-707.4 standard, the application layer 302 includes the communications application software running on the TE2 device 102. Typically, the communications application software includes a user dial-up interface. Dial-up interfaces, being xe2x80x9cuser-friendlyxe2x80x9d, allow the user to identify the type of serial MT2 device 102 connected to the TE2 device 102 as well as accommodating the entry of telephone numbers (e.g., an ISP""s modem telephone number) and use name/password scripts to originate a call The dial-up interface generally incorporates a dial-up engine which receives the telephone number inputted by the user and translates it into a command string. An exemplary command string is the AT dial command string that is compliant with the Hayes(copyright) Standard AT Command Set language. Examples of such AT dial command strings are: xe2x80x9cATDT 5551234xe2x80x9d and xe2x80x9cATDT#777xe2x80x9d. Artisans of ordinary skill will readily appreciate, however, that other interfaces may be used to generate command strings other than AT dial command strings with equal effect.
Responsive to the AT dial command string, the MT2 device 104 brings up an async call by first configuring a TCP-based connection to the BS/MSC 106 and then actuating the dialing operation of the telephone number included in the dial string command. The MT2 device 104 configures the TCP protocol 304 by opening a connection and specifying that the network layer protocol, IP 306, will be used for message transport. The IP protocol 306 transmits the TCP packets to the IP address specified.
After dialing, the MT2 device 104 must perform handshaking and training operations with the remote ISP modem 336 to establish the call The dial-up engine waits for the MT2 device 104 to send a xe2x80x9cConnectxe2x80x9d message back to the TE2 device 102, signifying that it has connected to the remote ISP modem 336. The Connect message then prompts the communication application software on the TE2 device 102 to commence the serial transmission of IP packets.
Each of the CDMA Data Service Options is identified by the Service Options defined in TIA/EIA IS-707.1. As illustrated in FIG. 4, the Service Options format includes a base service option number field which indicates the base data service (e.g., asynchronous data service, facsimile service, packet data bearer service, or secure telephone unit service). The Base Service Option Number identifies base data services, such as async data, fax, packet data, etc. The Service Option Revision identifies the data service features set. The first feature set for any base data service is assigned Service Option Revision 0, the next is assigned Service Option Revision 1, and so on, up to Service Option Revision 7.
FIG. 6 lists the Service Options used by CDMA data services. The Base Service Option Numbers 4 and 12 support async applications; Base Service Option Numbers 5 and 13 support fax applications; Base Service Option Numbers 7 and 15 support Internet Protocol (IP) and Connection less Network Protocol (CLNP) networks; Base Service Option Numbers 8 and 16 support the Cellular Digital Packet Data (CDPD) network; and Base Service Option Numbers 10 and 11 provide a secure traffic bearer service for digital U.S. Government STU III terminals.
The requirements for the Rm interface, CDMA Data Service Option selections, and the AT dial command processes are defined in TIA/EIA IS-707.3, entitled xe2x80x9cDATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: AT COMMAND PROCESSING AND THE Rm INTERFACE,xe2x80x9d published in February 1998 and herein incorporated by reference. The IS-707.3 standard specifies that the selection of either the base service options or base service features is controlled through the mobile station through the Hayes(copyright) Standard AT Command Set language. As illustrated in FIG. 1, a MS 103 includes a TE2 device 102 connected to an MT2 device 104 via the Rm interface. The TIA/EIA IS-707.3 standard presumes that a user, originating a call on a MS 103, selects the desired CDMA Data Service Options by configuring the xe2x80x9cAT+CRMxe2x80x9d parameters. FIG. 5 lists a subset of AT+CRM parameter commands for the CDMA Data Service Options. The default value for the AT+CRM parameter is zero if the value is supported by the MT2 device 104. If zero is not supported, the default value shall be manufacturer-specific.
A limitation of the CDMA Data Services Options, under the IS-707.3 standard, is its reliance on mobile users to enter the AT+CRM commands. In other words, to select the desired CDMA Data Service Options and features, the user must configure his selection through an unspecified interface on the TE2 device 102. The actual configuration of the AT+CRM parameter value may prove both inconvenient and challenging given the variety of options and parameters from which to choose. For example, if the call-originating user desires to bring up a particular packet data call (e.g., Mobile IP, Simple IP, Cellular Digital Packet Data, etc.) the user will not only have to decide which base service to choose, but also how to configure the AT dial commands to specify the desired options and features associated with that call.
Moreover, mobile users would have to engage unfamiliar interfaces and execute different procedures depending on their desired CDMA Data Service Option. For example, even though users maybe familiar with the application""s communication user interface for configuring an async call or modem emulation (i.e., IS-707.4 applications), users would have to manipulate other interfaces to establish other CDMA Data Service Option calls such as a packet data call.
One proposed solution, as presented in U.S. patent application Ser. No. 08/593,222, entitled xe2x80x9cAutomatic Data Service Selectionxe2x80x9d by James Wilkie, assigned to the assignee of the instant application, and herein incorporated by reference, automates the selection process of CDMA Data Service Options for a packet data call. Specifically, the proposed solution forces the selection of Packet Data Services whenever the MT2 104 device detects a Point-to-Point Protocol (PPP) encapsulated packet on the Rm link (See generally, Request for Comments 1661 [RFC 1661], entitled xe2x80x9cTHE POINT-TO-POINT PROTOCOL). This automatic selection occurs regardless of the AT+CRM parameter setting. Although this solution assists in selecting the Base Service Option, it still does not address the numerous options available within a particular service or their associated features. As such, the solution may not be able to uniquely identify all the desired CDMA Data Service Options.
What is needed is a system and method, that are both familiar and user-friendly, for a wireless communication device to determine mobile service options in a wireless communication system.
Systems and methods consistent with the principles of the present invention address the need identified above by providing a familiar and user-friendly system for determining the mobile data service option desired by a call-originating mobile user.
A system and method, consistent with the principles of the present invention as embodied and broadly described herein, includes a terminal device for originating a call and transmitting and receiving data in accordance with a selected data service option. The terminal device includes a communications interface for inputting a sequence of one or more alpha-numeric characters representing an AT dial command string in order to originate the call and for including information that indicates the selected data service option. The system also includes a communication device, coupled to the terminal device, for interfacing with the wireless communication system and for sending signaling messages to the terminal device. The communication device receives the AT dial command string from the terminal device and examines the contents of the received AT dial command string. The communication device compares the contents of said AT dial command string with stored pre-determined alpha-numeric character sequences. These character sequences include standard telephone numbers and reserved telephone number sequences representing different data service options. The communication device determines whether a match exists between the inputted sequence and the stored reserved telephone number sequences. If a match does exist, the communication device begins operating in a mode consistent with the selected data service option associated with the reserved telephone number sequence.